Photoluminescent polymeric micelles from poly(ethylene oxide)-block-poly(((4-vinylphenyl)ethene-1,1,2-triyl)tribenzene) diblock copolymers

Abstract

In this contribution, we report the preparation of photoluminescent polymeric micelles via the self-assembly of amphiphilic diblock copolymers. First, poly(ethylene oxide)-block-poly(((4-vinylphenyl)ethene-1,1,2-triyl)tribenzene) (PEO-b-PTPEE), a novel diblock copolymer bearing an aggregation-induced emission (AIE) fluorophore subchain (viz. PTPEE) was synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization. The diblock copolymers were well characterized by means of ¹H NMR spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). It was found that in bulk the PEO-b-PTPEE diblock copolymers were microphase-separated. In aqueous solutions, these diblock copolymers were capable of self-assembling into polymeric micelles, the sizes of which were dependent on the lengths of the PTPEE blocks. Notably, these polymeric micelles displayed photoluminescence (PL); the PL quantum yields increased with increasing the lengths of PTPEE subchains. The PL properties have been interpreted on the basis of the aggregation-induced emission (AIE) behavior of PTPEE blocks. In this work, we have explored the use of the photoluminescent micelles for the detection of a trace of picric acid in aqueous solution.